public class 不同路径 {
    public int uniquePaths(int m, int n) {
        int[] dp = new int[n + 1];
        dp[1] = 1;
        for (int i = 1;i <= m;i++) {
            for (int j = 1;j <= n;j++) {
                dp[j] += dp[j - 1];
            }
        }
        return dp[n];
    }
}
